No, that was a scuffle in the build up to the fight (Brock's first two appearances ending with Cena bleeding). I couldnt find a good picture or any info on it, but heres the just of Cena's head during the match (after the GnP like 30 seconds in).
Brock didn't knock him out, so why would he struggle to get back up? It was just exsessive roughness with the elbows.
WWE wrestlers also aren't allowed to blade anymore as a result of the "PG". If anyone bleeds in WWE it's legit. You could see the cut where the blood was coming from aswell and they stopped the match to towel his head so you knew it was real.